Transmitter for multiplex alternating-current telegraphy



May 26; 1925. I 1,539;158

A. CLAUSING TRANSMITTER FOR MULTIPLEX ALTERNA ING- CURRENT TELEGRAPH! Filed Sept. 9, 1922 M I I I IIH Patented May 26, 1925.

p e v r lssaisa UNITED STATES IPATVE'TOFFICE'.

ARTHUR CLAUSING, or BERLIN-CHARLOTTENBURG, GERMANY, Ass'Ie'Non- T0 SIEMENS & HALSKE, .AKTIENGESELL'SCHAFT, or sIEMENssmnT, NEAR BERLIN. GERMANY, A coiaroaarIoN or'oEnMANY.

TRANSMITTER FOR MULTIPLELX ALTERNATING-CURRENT TELEGRAPH Y.

Application filed September To all whom it may concern: V

Be it known that I, ARTHUR CLAUSING, a citizen of the German Empire, residing at Berlin-Charlottenburg, Germany, have invented certain new and useful Improvements in Transmitters for Multiplex Alternating-Current Telegraphy, of which the following is a specification.

In multiplex telegraphy with alternatingcurrent, the transmitters work generally in such a way that for each frequency a small oscillating thermionic tube is provided which transmits its alternating, voltage to the grid of a boosting tube for higher output capacity. The anode circuit of'the booster supplies then the pulsating direct current energy in the form of alternatingcurrent energy to the long-distance line to' which the boosters of the individualtransmitting stations are connected in parallel.

Such. an arrangement has the drawback that by the parallel-connection of a plurality of transmitters connectedto the line, vthe energy supplied from one transmitter to the line drops owing to partof said energy being consumed by the other transmitters.

The loss of energy is such that with two line is closed or opene telegrams about one half, with'three one quarter, with four one sixth, and @with' five one ninth, only of the energyv required for each telegram is supplied to the line, as has been proved by theory and ex eriments. L; The present invention has or its object to avoid such useless consumption of energy. Moreover, another purpose of the present invention is to telegraph at high speed. For

this particular purpose it is necessary that,

the oscillations of the particular frequency are transmitted to the amplifier and to-the line immediately at their tude at the moment the particular key controlling these currents is closed. It ,is also necessary for high speed telegraphy that at the moment 'tirequency particular oscillator should notiyary by the closure of the key, such as for instance through coupling reactances or the like. In other words, each ,of thel thel'mionic tube oscillators which, is should maintain its articular frequency nomatter whether the cg connecting it, to the To obtain these result's'it primari y necessary that no energy,

maximum 'ampli-' the key' controlling. a particular 1 is closedthe," frequency; of that used for transmitting.

9, 1922. Serial No. 537,150.

or at least no appreciable energy,

is drawn fromthe thermionic tube oscillator when it is connected to the line. In other words, the several oscillators should not furnish the oscillating en ergy Which is used for the line transmission.v This effect maybe obtained inwelLknown manner by using the tube oscillators only as controlling r'elays,-as' it were, for a'three electrode thermionic amplifier, which as is known, does not require any energy for controlling the output current variationsare only controllled by the variation'of 'tlie' :grid poten- In order to connect a plurality of thermionic tube oscillators in parallel to 'a common amplifier, it is also necessary for the success ful operation that no feed-back exists be tween the individual tube oscillators.

\ According tothe present ,inventionthis is attained by causing the individual oscillat-' ingtubes all to act upon the grid circuit of the gridcircuit. In suchamplifiers one single common booster, of which the:

anode circuit is, as usual, coupled with" the long-distance line. In particular the connection between the oscillators and the common booster or amplifier is made by means of aperiodic circuits, one of such circuits being coupled to the output circuit of each of the oscillators, each aperiodic circuit containing an ohmic resistancewhich is simultaneously located in the grid circuit of the amplifier, i

By keeping the grid circuit of the booster .current-less or approximately so; and by properly choosing the anode and grid pon, in .rv ana 'v aesiigaae the indisending tubes. Each vidual-oscill atlon or tt nti'als, almost. no energy isic'onsumed at the drawing shows a dia I i oscillation transformer t has a winding 2?,

which is closed resistance WI, "Wm Wm, Wrv and v' a key T1, TnfiTm, Tweed T respectively.

p g g -ohmio'res'istances a in. se esath e b i g n e t t o e over av high-ohmic bifilar I all connected side to the grid G of a large boosting tube V and at the other side over a source of gridbias potential 0 to'the negative side f the cathode F, which is heated by the source A.

If, n such an arrangement, no grid current flows in the booster, which can be well attained by an increase of the anode voltage, 'e. g. by 'a displacement of the charac teristic to the negative region, firstly, the

transmitters do not act upon each other and,

, secondly, a simple addition of the alternating voltages of the individual transmitters takes place. Between grid and cathode of the booster acts the sum of the alternating voltages of the individual transmitters which control the anode current. The anode pulsating current is transmitted over the transformer U to the long-distance line as alternating current.

tubes through their individual key to the booster gridcircuit, the oscillating energy of the particular tube is at once supplied at the full amplitude, without variation in freuency, due to reaction. This is rendered possible by the location of the keys T T{, in aperiodic circuits.

Furthermore, since practically noeurrent flows in those aperiodic circuits, substantially no energy is drawn from the individual oscillators I-V when thuscom'iected to the booster circuit. &

By thus connecting anyof the oscillating Moreover, it is immaterial for the individual operation of the tube oscillators or transmitters whether one or more of them are at Work. If only one transmitter is operating, the remaining transmitters still connected to the grid do not consume or absorb any energy supplied from the first transmitter on account of their connection with the system hrough aperiodic circuits. One of the advantages of the present system is that the initial cable voltage resulting from one transmitter does not vary by 0105- o its circuits, and containing an ohmic re- 1 sistance and an operating key, and one common thermionic tube amplifier for all of said transmitters having a. grid circuit in.

which the resistances of all of said aperiodic circuits are arranged in series;

In testimony whereof I afix my signature.

ARTHUR GLAUSING. 

